deciphering python computations

guys i'm going to go nuts, i cannot figure out these computations....0.0
i see astersks everywhere!

http://gyazo.com/212863131d7ecf387eeb1875c8e2ba40.png

why does it keep adding 2????
0.o

what is causing this pattern no matter what the input is?

(block + line) * 2

in a loop where line increments... +2 anyone?